JOINT IMAGING CORE ABSTRACT The objective of the Joint Imaging (JI) Core of the Microenvironment in Arthritis Resource Center (MARC) is to facilitate research in the San Diego community focused on the biology of the joint through magnetic resonance imaging (MRI). The JI Core will provide a non-invasive means to image in vivo tissue structure, metabolism, and function of human and small animal joints. The Core's technologies can also provide structured data that can be analyzed and integrated with other datasets, such as transcriptomics from biopsies on the same joint and clinical phenotype. The Core offers a unique integration of radiology and rheumatology that is uncommon among Rheumatic Diseases Research Resource-based Centers, particularly when combined with the computational support from other MARC resources. The non-invasive nature of MRI, coupled with the absence of ionizing radiation and the ability to evaluate all musculoskeletal tissues, renders this resource highly valuable for joint pathology projects and for translational studies aimed at development of biomarkers or novel therapeutic approaches. The Aims of the JI Core are 1) to provide investigators with MR imaging protocols that offer non-invasive morphologic, biochemical and functional evaluation of musculoskeletal tissues, 2) to provide investigators with MR engineering support to include MR compatible devices and radiofrequency (RF) coil development for in vivo, tissue specimen or animal imaging, and 3) to assist investigators with imaging data post-processing algorithms that allow desired expression of data. The Core will also facilitate interactions of pre-clinical investigators with established rheumatology and orthopaedics clinical research resources and with affiliated services if non-MRI small animal imaging is needed. The JI Core will act as catalyzer of multi- disciplinary and innovative science that and bring human imaging technology to basic science investigators.